In many medical procedures, a catheter or other different kind of devices are inserted into tube systems like the arterial system of a patient, and guided to a target location inside the body. This procedure is generally done under imaging guidance using for example a C-arm type of a fluoroscopic apparatus. Periodically, the operating physician takes an X-ray snapshot to see where the tip of the catheter is located or, in the event of difficult manipulations, these are performed by the physician under continuous fluoroscopic imaging.
C-arm based X-ray imaging is the modality of choice for many vascular interventions. In applications such as neuro vascular or hepatovascular treatment, the treatment is often complicated by the complexity of the underlying vascular structures. Due to strong overlap of the often small, tortuous and diseased vessels, angiographic interpretation can be a very laborious task which requires multiple contrast agent injections to visualize the vessel tree from different hierarchy levels. Thereby contrast agents are elements or compounds used to improve the visibility of internal bodily structures in for example an X-ray image.
Further on, it has to be differentiated between interventional imaging, which is applied continuously, with a low dose of radiation and which is for navigation or surveillance and between diagnostic angiography, which uses high doses to improve diagnosis and therapy decisions.
State of the art angiographic imaging relies on two dimensional (2D) sequences and/or on static three dimensional (3D) reconstructions. Although 2D imaging is dynamic, which means that the inflow and the distribution of the injected contrast agent bolus can be surveyed, it is often impossible to resolve the exact vessel topology. 3D imaging overcomes many of these limitations since the vessel tree can be examined from multiple perspectives. But due to the static an often unselective character of the reconstruction assessment of the hemodynamic interrelations is still a challenging task.